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# Welcome to our Brain Teasers Questions and Answers Page

A brain teaser is a form of fun puzzle that requires thought to solve which often requires thinking in unconventional ways.

### Brain Teasers I

1. What is the maximum number of different ways to rearrange four books on a shelf?
2. What the probability of getting 5 heads in a row when flipping a coin?
3. My grandson is about as many days old as my daughter is in weeks, and my grandson is as many months as I am in years. Totalling my grandson's, my daughter's and my age, we are 120 years old. Can you tell me my age in years?

4. A shopper paid a £17.28 bill in four different denominations of coins. The largest denomination was £1 and he used exactly the same number of each coin. How many of each coin was required and what were the coin values?
5. Carole was born on December 25th, yet every leap year her birthday is always in the summer. How is this possible?
6. A ship in a harbour has a fixed metal ladder over the side with six rungs under water. Each rung is two inches wide and ten inches apart. If the tide rises at the rate of six inches per hour, how many rungs would be submerged in four hours?
7. What number is missing from the sequence:
1, 8, 27, 64, ?, 216
8. You're a runner in a cross-country race. Just before crossing the finish line, you overtake the person in second place. In what place did you finish?
9. What do the following words have in common: awning, east, ear and earned?
10. What's the bay number occupied by the parked car?

11. If EP = 12 and HU = 14 what does BF = ?
12. There are three downstair switches. Each corresponds to one of the three light bulbs in the attic. You can turn the switches on and off and leave them in any position. If you are only allowed one trip into the attic how could you identify which switch corresponds to which light bulb?
13. You are a prisoner. The evil queen offers you a chance of freedom by playing a game of chance. You're given 50 black marbles, 50 white marbles and 2 empty bowls. The queen then says, "Divide these 100 marbles into these 2 bowls. You can divide them any way you like as long as you use all the marbles. Then I will blindfold you and mix the bowls around. You then can choose one bowl and remove one marble. If the marble is white you're free, but if the marble is black, you will stay in prison." How do you divide the marbles up so that you have the greatest chance of a 'white' marble and freedom?
14. The name of the fourth son? Someone's mother has four sons...North, South and East. What is the name of the fourth son.

1. Twenty-four
2. 1 in 32, 1/32 or 3.125%
3. Grandson: 6 years. Daughter: 42. Grandfather: 72.
4. 16 of each of £1, 5p, 2p and 1p.
5. Carole was born in the Southern Hemisphere (a leap year or non-leap year is not relevant and just put in to confuse)
6. Six rungs still! The ship and hence ladder will rise with the tide.
7. 125 (they're cubes, from 1 to 6)
8. Second Place. If you pass the person in second, you take second place, and they become third.
9. They all make new words with the letter 'y' placed in front.
10. 87. Look at the image from an upside down direction.
11. 5 (the number of places between the letters alphabetically, including the letters)
12. Keep the first bulb switched on for a few minutes and it gets hot. Then, switch it off, switch another one on, walk into the attic and one light will be hot (first switch), the second will be lit, and the third will be off and cold.
13. Place 1 white marble in one bowl, and place the rest of the marbles in the other bowl (49 whites, and 50 blacks). This way you begin with a 50/50 chance of choosing the bowl with just one white marble, and freedom! But even if you choose the other bowl, you still have almost a 50/50 chance at picking one of the 49 white marbles.
14. What (a lot of people say 'Someone'. There's no question mark, it's a statement.)

### Brain-teasers II

1. If John works one shift every second day, Paul works once every third day, and Jane works every fifth day, how often do all three colleagues work together?
2. What number should appear next in this sequence?
1, 5, 12, 34, 92, 252, ...?
3. A miller has one sack of wheat, which he grinds into flour. He then fills two sacks with the flour which are as large as the original sack of wheat. How is this possible?
4. What letter should replace the question mark in this sequence?
B C D G J ? P
5. A clock was correct at midnight. From that moment it began to lose three minutes per hour. The clock stopped 90 minutes ago showing 17:06. The clock runs for less than 24 hours. What is the correct time now?
6. A man is standing at the edge of the forest, how far can he walk into the forest?
7. There are two rooms with signs on the door. These signs were either both true or both false. Here are the signs:

ROOM I: EITHER A LION IS IN THIS ROOM OR A LADY IS IN THE OTHER ROOM

ROOM II: A LADY IS IN THE OTHER ROOM

Does the first room contain a lady or a lion? Does Room II contain a lady?

8. I did have money in my wallet. I gave half away and of what remained, I spent half. Then, I lost five pounds, which left me with just five pounds. How much money did I start with?
9. A red house has four walls. All the walls are red and are facing south, and a bear is circling the house. There's also a red storage container outside. What colour is the bear?
10. If you had a 5-litre bowl and a 3-litre bowl, and access to a tap, how would you measure exactly 4 litres?
11. In two years Bob will be twice as old as he was five years ago. How old is he?

1. Every 30th day (2 x 3 x 5)
2. 688. Add the two previous numbers then multiply by 2.
3. He put one bag inside the other before filling it.
4. It's O. In alphabetical order letters that have curved rather than straight edges. (Sorry... quite hard I thought!)
5. 19:30

6. Halfway, then he would be walking out again.
7. Room I has a lady. And Room II has a lady.
8. 40 pounds
9. White. The house must be on the north pole for all the walls to face south and the only bears in the north pole region are polar bears.
10. Fill the 5-litre bowl and pour water to the 3-litre bowl, which you empty afterwards. From the 5-litre bowl pour the 2 remaining litres to the 3-litre bowl. Refill the 5-litre bowl and fill in the 3-litre bowl (with 1 litre), so there stay the 4 required litres in the 5-litre bowl.
11. He's 12. In two years Bob will be 14, half that age is seven the age he was five years ago.